Lung Volume Reduction Surgery (LVRS)
Lung volume reduction surgery (LVRS) is a promising new treatment for certain patients with moderate to severe symptoms from emphysema. Medical management, including pulmonary rehabilitation, has been shown to improve exercise tolerance, to reduce oxygen requirements during exercise and to probably reduce hospitalization for patients with severe emphysema, but it does not improve pulmonary function.
By improving the elastic recoil of the lung, LVRS is the first treatment to demonstrate improvement in pulmonary function and quality of life for selected patients with emphysema. The most important selection factor for LVRS is the presence of a heterogeneous pattern of emphysema. This means there are parts of the lung that are not functional, and parts of the lung that function better. The basic concept of LVRS is to remove parts of the lung that do not work so the other areas of the lung can work more effectively. Because a heterogeneous pattern is found in only 20% of patients with emphysema, only a minority of patients are candidates for the procedure.
Published reports indicate that the optimal approach appears to be a bilateral (both lungs) staple operation during a single anesthetic. This procedure offers a 68% chance of oxygen independence, an 85% chance of prednisone independence and a 60 to 70% improvement in pulmonary function for patients with an upper lobe distribution of emphysema. The long-term benefits of the procedure are currently unknown, but there are several studies comparing LVRS with maximal medical management.
The nonsurgical treatment of emphysema has only shown limited efficacy and no improvement in pulmonary function for patients with emphysema. LVRS is a promising new treatment that has shown improvement in pulmonary function for selected patients. The procedure involves cutting away severely destroyed, nonfunctional areas of lung tissue to reduce the size of hyperinflated lungs to allow the remaining lung tissue to function more effectively.
The information below will describe the background of medical treatment for severe emphysema, the development of surgical procedures for emphysema, the techniques of LVRS, the mechanism for improvement following the procedure and early results for LVRS.
The goals of medical treatment are improving functional capacity and quality of life. Medicines and inhalers can help minimize airflow limitation. Two clinical trials have shown that the use of supplemental oxygen therapy to maintain the oxygen saturation at greater than 90% prolongs survival. Functional capacity is reached with exercise conditioning, respiratory muscle training, nutrition and psychosocial training. A review of a study involving 900 patients who underwent pulmonary rehabilitation has shown that these programs reduced oxygen requirements, lessened increased heart rate and increased exercise tolerance. Pulmonary rehabilitation, however, does not improve pulmonary function tests and does not slow the deterioration of pulmonary function tests.
Because medical treatment has shown only limited efficacy, many different operative procedures were tried unsuccessfully early in the 20th century until the 1950s, when Otto Brantigan, MD, performed wedge resections (cutting out emphysema diseased tissue) from the lung to reduce the overexpansion. Although 75% of patients reported significant clinical improvement, the lack of objective documentation for this benefit and the 18% operative deaths prevented widespread acceptance of his procedure.
In 1991, Akio Wakabayashi, MD, rekindled the interest in surgical treatment of emphysema with the use of unilateral (one sided) thoracoscopy (examination of lung with a small scope) to shrink the lung with the Nd: YAG laser. Although a large number of patients underwent the procedure, no good scientific documentation of results was forthcoming.
In 1994, Joel Cooper, MD, modernized Dr. Brantigan's operation by resecting areas of severe emphysematous change in both lungs through a median sternotomy (incision through the middle of the chest bone). Because significant air leaks occurred early in his experience, he developed bovine pericardium, a substance used on the staple lines to close the air leaks.
For the 20 patients in this initial series, the operation produced an average 82% increase in pulmonary function tests. The substantial differences in these operative techniques led to controversies about whether the operative procedure should be unilateral or bilateral, be performed with the laser or staples, and be an open or closed procedure.
Patients who are candidates for LVRS have moderate to severe symptoms from emphysema, despite maximal medical management. The standard evaluation includes a medical history and physical, chest X-rays, high resolution chest CT scans, an arterial blood gases test, plethysmography (measures and records changes in lung function), lung perfusion scans and the six-minute walk. The patients are usually oxygen dependent, severely restricted in activities, and experiencing considerable difficulty with dressing, showering and walking short distances. Patients are normally younger than 75 years of age, but selected older patients may be candidates for LVRS.
The procedure is generally not recommended for patients who are too severely incapacitated (e.g. ventilator dependent, wheelchair dependent and with severe hypercarbia-increased carbon dioxide in the blood). Severe anxiety and depression limit patient compliance with exercise programs, which leads to poor postoperative participation in exercise. CO2 retainers (>55 mmHg) can undergo the procedure if they otherwise have a perfect radiological pattern and are highly motivated. Patients who use four liters of nasal O2 either do not improve (50%) or only improve a minimal amount (50%).
Pulmonary function tests show severe obstructive disease (FEV 1<40%) and significant hyperinflation. Patients with an (pulmonary function test) FEV 1<500 ml can benefit significantly, but they do have an increased risk for the procedure. These patient selection guidelines are generally empiric without good scientific data to support the criteria.
Candidates for LVRS must have significant, localized parenchymal pulmonary destruction in areas of the lung, so the most important selection factor is the radiological pattern of the emphysema. The chest CT scan generally shows areas where the lung tissue has been replaced with one- to two-centimeter holes. This should be in a heterogeneous pattern with severe parenchymal destruction in part of the lungs (usually the upper lobes) on the chest CT scan and little bloodflow to the corresponding area on the lung perfusion scan (Figure 1).
The anatomic and radiological patterns of emphysema determine that only a small percentage of patients who have symptoms from severe emphysema are candidates for the procedure. For all these reasons, a high percentage of patients screened for LVRS are not candidates.
The loss of elastic recoil with progressive emphysema results in progressive overinflation of the lung, as shown by increasing total lung capacity and residual volume. Following successful LVRS, a significant improvement in elastic recoil leads to improvement in shortness of breath and exercise tolerance. These changes are all related to changes in lung compliance with no significance in chest wall mechanics.
After a complete evaluation, patients should undergo a pulmonary rehabilitation program that includes an aggressive exercise program. This optimizes their physical condition, reduces their operative risk and decreases the need for inpatient pulmonary rehabilitation following the operation. It is also useful as a screening test for patients because they are not candidates for LVRS if they lack the motivation to successfully complete the program or cannot control their anxiety enough for the exercise program. Most centers use preoperative pulmonary rehabilitation, although there is no study that has proven its benefit.
LVRS can be performed as an open or closed procedure. Dr. Cooper originally chose to perform LVRS through a median sternotomy (open up the middle of the chest) to operate on both lungs during a single anesthetic. That incision is also much less painful than bilateral thoracotomies. This approach offers good exposure for emphysema located in the front or the apex of the lungs. Emphysema at the back of the lungs or adhesions are less accessible. Lower lobe resections are more difficult, especially on the left.
Alternatively, the procedure can be performed with video-assisted thoracoscopy surgery (VATS). This positioning offers the optimal exposure of all areas of the chest, including the lower lobes and the back, where adhesions are found. It does, however, require good video skills and two separate skin preps. This is the approach for the operation developed at Cedars-Sinai, and performed by Cedars-Sinai physicians more than 500 times. The median sternotomy offers the flexibility to have simultaneous access to both sides with one prep.
The techniques and result of minimally invasive, video-assisted lung volume reduction surgery. In minimally invasive, video-assisted lung volume reduction surgery (which may also be called thoracoscopic or endoscopic LVRS), the surgeon makes three to five incisions through which a video camera is inserted. The camera allows the surgeon to guide the instruments, which are inserted through the same incisions as the camera. Usually, lung volume reduction surgery reduces lung volume by 30 to 40 percent.
The procedure is performed under general anesthesia with a double lumen endotracheal tube inserted into each lung to help the patient breathe during the operation and an epidural catheter inserted in back for postoperative pain management.
The amount of lung removed is determined by the areas of severe destruction seen on the preoperative CT scan and the lung perfusion scan. For upper lobe emphysema, approximately 50 percent of each upper lobe is removed (approximately 75 grams of tissue per side), and an even larger amount is removed for lower lobe emphysema. Essentially, the entire lobe is removed if there is no perfusion in the entire lobe.
The patients are routinely extubated (breathing tube removed) in the operating room and transferred to the intensive care unit. Less than 5% of patients require re-entubation (putting the breathing tube back in to help the patient breathe). Patients are out of bed on the day of the procedure. Arterial blood gases are initially low, but these usually return to normal over the next few days. The epidural catheter (tube inserted to give the patient pain medication) and Foley catheter (tube in bladder) remain for three postoperative days. The chest tubes are for water drainage and not suctioning. If there is still an air leak after three days, Heimlich valves are placed on the chest tubes.
Many publications address controversies regarding operative technique for LVRS. In a randomized, prospective study, we demonstrated the superiority of the resectional (staple) technique compared to the shrinkage (laser) technique (33% versus 13.4% improvement in FEV 1 at 6 months). Two years after the laser treatment, only one of 33 patients (3%) had any benefit from the procedure. In contrast, 11 of 39 staple treated patients (28%) retained benefit from the procedure. These results are consistent with the results of nonrandomized series that used either the staple or laser procedures, so the staple procedure appears to be the technique of choice.
To determine the role of unilateral and bilateral procedures, we reported a nonrandomized comparison of unilateral versus bilateral staple operations. Data analysis failed to identify factors that could allow selection of patients that benefit enough from a unilateral procedure. A bilateral procedure, therefore, is recommended as the procedure of choice for patients with a bilateral pattern of heterogeneous emphysema. Results from other series of unilateral or bilateral procedures are consistent with these results.
The operative mortality for bilateral LVRS is 5 to 10%. The average length of stay has been 12 to 16 days. Air leak lasting at least seven days has occurred in 35 to 50% of patients. Other complications in less than 5% of patients include pneumonia, arrhythmias, myocardial infarction and bleeding.
The results with bilateral staple LVRS appears to be comparable, whether the procedure is performed with VATS or a median sternotomy. Kotloff and Wisser reported similar results in nonrandomized comparisons of the VATS and median sternotomy techniques at the same institutions.
Overall, in our experience, approximately 80% of patients improve, 15% fail to improve and the operative death is 5%. The length of time that the benefit lasts following LVRS is unknown at the present time. For some patients the benefit lasts only six to 12 months. Approximately half of our patients maintain good improvement for at least two years. Future studies will better define the length of benefit from LVRS.
Bilateral staple LVRS is the standard operative procedure recommended for the majority of patients who are candidates for LVRS. The results with VATS and median sternotomy appear to be comparable. Unilateral LVRS is reserved for patients without the pattern of emphysema on the opposite side or with a contraindication to operating on the opposite side. There is no apparent role for the current laser technology in the treatment of emphysema.
LVRS allows the removal of lung cancer in some patients who are otherwise not candidates for resection, due to poor pulmonary function. If the cancer and the emphysema are in the same part of the lung, a formal anatomic lobectomy (removal of a lung lobe) and lymph node removal can be performed. If the lung cancer is in the better part of the lung, a wedge resection and LVRS can be performed.
LVRS and lung transplantation can be alternative treatments for some patients, and each may be the procedure of choice. Gaissert concluded that LVRS achieved satisfactory improvement in disabling symptoms while avoiding immunosuppression and transplant specific complications. In some cases, LVRS may act as a bridge to transplantation. It may be the only surgical option for some patients (e.g., patients too old for transplantation), while transplantation may remain the only surgical option for other patients (e.g., patients who do not have a pattern of emphysema suitable for LVRS).
In 1994-95 there was limited data regarding LVRS efficacy and patient selection. Several controlling bodies concluded that the procedure needed to be controlled to obtain adequate scientific documentation of efficacy and to ensure patient safety. Hence, the Health Care Financing Administration (HCFA) stopped payment for LVRS on Dec. 9, 1995. In an unprecedented move, HCFA and the National Institutes of Health (NIH) decided to work together with the medical community to study the procedure. HCFA agreed to pay patient costs, and the NIH agreed to choose participating centers of excellence, develop a protocol and oversee the execution of the protocol. The study, called the National Emphysema Treatment Trial (NETT) opened in late 1997 and was completed in 2002. The results of the NETT were published in the New England Journal of Medicine. This showed that patients with upper lobe emphysema had better pulmonary function and exercise tolerance after LVRS than after medical treatment. For patients with upper lobe emphysema and poor exercise tolerance, the survival was better after LVRS than after medical treatment.
Six randomized, prospective studies comparing LVRS with maximal medical management have now been completed. The results of all studies show that patients fare better after LVRS than after medical management.